5.2 Classification
of Useful Properties
The stress-strain relationship, which is
often crucial for mechanical applications, is illustrated
in Figure 80 using the example of a steel, an Al2O3 ceramic
and a thermoplastic. The limited breaking elongation of the
ceramic compared to that of metals, combined with an often
significantly lower fracture toughness KIC, is generally to
be considered a disadvantage, although it simultaneously entails
the advantage of dimensional stability, in particular at high
temperatures.
Figure 80: Stress-strain behaviour of selected
materials
(*) Data not usually provided
Table 8: A comparison of typical mechanical
characteristics of some ceramics with grey cast-iron and construction
steel
Table 9: Technical aspects
and relevant properties of ceramics
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